基于“源-汇”理论的海口城市景观格局与热岛效应响应机制

城市化引起的土地利用/覆被变化加剧了热环境恶化。以2000、2005、2010、2015年和2018年5期Landsat遥感影像为数据源，选择热场变异指数、汇源景观贡献度和景观效应指数，分析海口陆域在城乡梯度上的源汇景观格局对城市热环境的贡献及其生态效应。结果表明:1）热岛梯度演变集中于西海岸、中心城区和江东新区等区域。2）不同汇源景观的平均热场变异指数不同，呈裸地>人工表面>源景观>灌木草地>农田>汇景观>林地>水体的规律。3）源、汇景观在中心城区对热岛贡献值最大，沿着梯度方向对热岛贡献度逐渐降低；随着城镇不断扩张，在城乡梯度方向汇区比例不断增大、源区比例不断减小，导致了热岛的空间转移与扩散。4）景观效应指数在中心城区段（T1～T7）沿城乡梯度快速递减且促进热岛比例大；在郊区段（T8～T21）波动上升且缓解热岛比例大。由此，提出基于区域景观系统理论的热岛缓解策略。

Urban Landscape Pattern and Response Mechanism of Heat Island Effect Based on “Source-Sink” Theory of Haikou City

Land use/cover changes caused by urbanization have exacerbated the deterioration of the thermal environment.Based on the Landsat remote sensing images from 2000,2005,2010,2015 and 2018,the heat index (HI),source and sink landscape contribution index (CI) and landscape effect index (LI) were selected to analyze the contribution of source and sink landscape pattern on urban and rural gradient of Haikou land area to urban thermal environment and its ecological effect.The analysis showed that 1) the gradient evolution of heat island was concentrated in the west coast,central urban area and Jiangdong New Area.2) Mean heat indices of different source and sink landscapes were different,showing the law of bare land>artificial surface>source landscape>shrub grassland>farmland>sink landscape>forest land and water.3) Source and sink landscapes contributed the most to the heat island in the central urban area,and the contribution degree to the heat island decreased gradually along the gradient direction.4) Landscape effect index decreased rapidly along the urban and rural gradient in the central urban area (T1-T7) and promoted the large proportion of heat islands,and fluctuated in the suburban section (T8-T21) and alleviated the large proportion of heat islands.Therefore,the heat island mitigation strategy based on regional landscape system theory was proposed.